Systematic Identification of Modern Analogs for Reservoir Modelling

Abstract

Facies based reservoir modeling has long been influenced by studies of outcrop analogs and modern systems. Outcrops typically provide cross sectional data on element geometries while modern systems provide data on the plan view dimensions of elements and their lateral relationships with surrounding facies. The advent of free remote sensing data (Google Earth etc) has improved the availability of modern analogs but selection is commonly undertaken on an adhoc basis and it can be difficult to identify suitable parts of the World to use. The goal of this study has been to develop a methodology for the systematic identification of modern analogs based upon parameters such as, depositional environment and processes; tectonic setting and basin type; climate and latitude. The second stage is to automatically extract geometric data from architectural elements as inputs for reservoir modeling. Given that sedimentary systems in basins are significantly different to their counterparts in areas of net erosion, the first stage of the work was to distinguish modern day basins from areas of net degradation at a global scale. This was done using a series of GiS layers which mapped combinations of gradient and bedrock geology. The result suggests that only 16% of the Earth's land surface lies within basins. The remainder will not be represented in any future rock record and should not be used for analog studies. The second stage of the work flow was to superimpose layers for climate and tectonic setting. The results of this work suggest that arid systems are over represented in basins (27% of earths land but 60% of basins). To address depositional process in the shallow marine realm, a model was built which incorporates data on tidal range, mean wave height and proximity to, and size of, fluvial input points. This allows a relatively coarse (5km segments) classification of the global coastline on a WTF plot. Classification of continental environments was based on subdivision into fluvial, eolian and lacustrine. This was achieved at the global scale by the automated identification of water bodies (lacustrine systems) and the mapping of eolian deposits. As with the shallow marine systems these can then be subdivided by climate, basin type and latitude. Final a series of tools have been developed to automatically extract geometric data on architectural elements for input to object-based, variogram-based and multi-point statistical reservoir modelling packages.

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015